Automated diagnostic analyzers employ multiple carousels and multiple pipetting mechanisms to automatically aspirate fluid from and dispense fluid to different areas in the analyzer to perform diagnostic analysis procedures. The carousels may include a carousel for reaction vessels, a carousel for samples and/or a carousel for reagents. By arranging multiple containers on the respective carousels, these known analyzers are capable of conducting multiple tests on multiple test samples as the carousels rotate. Some known carousels are arranged in a coplanar orientation, and a number of different modules or stations are disposed around the carousels to perform specific functions such as, for example, mixing the contents of a reaction vessel, washing a reaction vessel and/or a pipette, incubating a test sample, and analyzing the contents of a reaction vessel. Due to the multiple coplanar carousels and the number of modules and stations, these known automated clinical analyzers typically require a relatively large space.